terabyte

A terabyte (derived from the prefix tera- and commonly abbreviated TB) is a measurement term for data storage capacity. The value of a terabyte is based upon a decimal radix (base 10) and is defined as one trillion (short scale) bytes, or 1000 gigabytes.

The number of bytes in a terabyte is sometimes stated to be approximately 1.0995 x 10¹². This difference arises from a conflict between the long standing tradition of using binary prefixes and base 2 in the computer world, and the more popular and intuitive decimal (SI) standard adopted widely in the industry. Standards organizations such as IEC, IEEE and ISO recommend to use the alternative term tebibyte (TiB) to signify the traditional measure of 1024⁴ bytes, or 1024 gibibytes, leading to the following definitions:

• According to the SI standard and current usage, a terabyte (TB) contains 1,000,000,000,000 bytes = 1000⁴ or 10¹² bytes.

• According to traditional and binary arithmetic, a terabyte contained 1,099,511,627,776 bytes = 1024⁴ or 2⁴⁰ bytes. This amount is now known instead as a tebibyte, to avoid confusion.

The capacities of computer storage devices are traditionally advertised using their SI standard values.

Terabytes in use

• The National Archives of Britain, which hold 900 years of written material, contains nearly 60 terabytes of data.
• The U.S. Library of Congress Web Capture team has claimed that "as of May 2007, the Library has collected more than 70 terabytes of data"^[1]
• Ancestry.com claims approximately 600 terabytes of genealogical data with the inclusion of US Census data from 1790 to 1930.^[2]
• IsoHunt the BitTorrent Tracker claim they track nearly 600 terabytes of Torrent addressed files.^[3]
• [[1].[CASTOR]] @ CERN is almost reaching 10000 TB of physics data.
• A human being's functional memory has been claimed as 1.25 terabytes, according to Raymond Kurzweil in The Singularity Is Near, p. 126. However, this is not widely accepted.
• Rapidshare has over 3000 terabyte (3 petabyte) of space used for hosting files.^[4]
• One hour of uncompressed Ultra High Definition Video (UHDV) consumes approximately 12 terabytes of data.
• A Holographic Versatile Disc (HVD) can hold up to approximately 4 terabytes.
• 3D optical data storage solutions that offer TB-level storage capacities are being actively developed by several companies.
• A Protein-coated disc (PCD) could theoretically hold approximately 50 terabytes of data if individual protein molecules could be addressed.
• Personal computers and related devices such as TiVos containing a terabyte or more of storage space have recently become practical using combinations of high-capacity mass-market hard drives.
• In March 2007, Hitachi released the first commercially available consumer 1 TB drive, which uses five approximately 200 GB platters and perpendicular recording.^[5]
• LaCie has released an approximately 2 TB external hard drive.^[6]
• As of 2007 the largest monolithic hard drive in the world, the Hitachi 7K1000, has 1 TB of data storage capacity. Seagate also has a 1 TB drive; on paper it was the first terabyte drive, but Hitachi was the first to ship one.
• Alienware has now released an approximately 4 terabyte hard drive, the largest offered on a PC.^{[citation needed]}
• Bungie.net has announced that it has approximately 70 terabytes in its Halo 3 Data bin.
• Apple Inc. has released a new iMac with a hard drive disk upgrade of up to 1 terabyte.
• Hitachi announced (on 15th of October 2007) that it will release a 4 terabyte hard drive for desktop computers and a 1 terabyte hard drive for laptops using current perpendicular-to-the-plane giant magneto-resistive technology (680news). ^[7]

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